PRODUCT Function
multiplies matrices of polynomials
- PRODUCT(
,
, dim>)
The inputs to the PRODUCT function are as follows:
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- is an
numeric matrix.
The first
submatrix contains the constant
terms of the polynomials, the second
submatrix contains the first-order terms, and so on.

- is an
matrix.
The first
submatrix contains the constant
terms of the polynomials, the second
submatrix contains the first-order terms, and so on.
- dim
- is a
matrix, with value
.
The value of this matrix is used to set the dimension
of the matrix
.
If omitted, the value of
is set to 1.
The PRODUCT function multiplies matrices of polynomials.
The value returned is the

matrix of the polynomial products.
The first

submatrix contains the
constant terms, the second

submatrix
contains the first-order terms, and so on.
Note: The PRODUCT function can be used
to multiply the matrix operators employed in
a multivariate time series model of the form
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where
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,

,

, and

are matrix polynomial operators whose
first matrix coefficients are identity matrices.
Often
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and

represent seasonal components
that are isolated in the modeling process but multiplied with the
other operators when forming predictors or estimating parameters.
The RATIO function is often employed
in a time series context as well.
For example, the following statement produces the matrix
, as shown:
r=product({1 2 3 4,
5 6 7 8},
{1 2 3,
4 5 6}, 1);
R 2 rows 4 cols (numeric)
9 31 41 33
29 79 105 69
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